Jeff Arch, who penned the 1993 rom-com starring Tom Hanks and Meg Ryan, has reportedly begun work on a draft script.
The production is expected to retain the storyline from the original movie, which focuses on a young boy trying to find a date for his widowed father.
Composer Leslie Bricusse, who has written songs for films including Doctor Dolittle and Willy Wonka And The Chocolate Factory, has completed around 18 songs for the show to date.
My Big Fat Greek Wedding director Joel Zwick will helm the project, which is being developed by David Shor's Sleepless In Seattle Management.
The musical is expected to be ready for 2010, when it could face competition from fellow movie adaptations The Addams Family, which opens in April, and Spider-Man: Turn Off The Dark, which is slated for a February premiere.